1. Field of the Invention
The present invention relates to an electrochemical test strip, and in particular relates to an electrochemical test strip with an underfill detection function.
2. Description of the Related Art
Referring to FIG. 1, a conventional electrochemical test strip comprises a set of identifying electrodes D, insulated from each other. When a sample is injected into the strip and through a set of reaction electrodes E to the set of identifying electrodes D along a direction A, the set of identifying electrodes D are electrically conducted through the sample to form a circuit. The circuit can be electrically connected to an instrument for determining fill or under fill of the sample.
However, the conventional electrochemical test strip requires at least two pins for the additional set of identifying electrodes, thus reducing the number of available pins and obstructing the expansion for other functions.
Further more, a conventional electrode structure comprises a reaction area between an upper electrode and a lower electrode (face to face structure) for determining the hematocrit ratio by flowing speed. When the sample contacts the reagent in the reaction area, the electronic signal between the upper and lower electroedes starts to highly increase by the chemical reaction between the sample and the reagent, when the sample contacts electrode without reagent, the electronic signal starts to highly decrease, and the time interval between the highly increasing and decreasing times of the electronic signal can be used to calculate flowing speed and the hematocrit ratio of the sample. However, the electrodes of the face to face structure could be conducted to each other by compressing the strip, and the flowing speed could be affected by the coating of the reagent on the reaction area.